Heat exchanger, such as radiators and condensers, conventionally consist of plural tubes extending between two tanks each for coolant or refrigerant or two headers (each associated with a tank) with fins (also called separators) disposed between the tubes. Usually there are also two end fins to cover the exposed surface of the two end tubes. To protect the end fins and to provide structural support and rigidity to entire unit, two support members (referred to hereinafter as side plates or side members), one on each end, extends between the headers or the tanks, as the case may be. These two side plates then form part of the outer periphery of the heat exchanger.
In use, hot fluid passes through the tubes and a passage of air over the tubes and the fins reduces the temperature of the fluid. However, since the overall temperature of the tubes is relatively high, the tubes thermally expand by a substantial amount with respect to their length when cold.
U.S. Pat. No. 3,939,908 relates to a radiator in which the problem caused by expansion of the tubes and a lesser degree of expansion of the side plates of the radiator is mitigated, by an expansion joint system.
The present assignees have provided a first solution to the problem of thermal expansion, which can lead to high stress in the tubes, or in the joint between the tube and the tank or header, by cutting the side plate of the heat exchanger which thereby allows the tubes to expand. This technique has however proved problematic. Firstly, cutting the side plate after brazing the tubes to the tank creates an additional operation which increases the cost of the heat exchanger. Cutting the plate is liable to increase the likelihood of the tubes being damaged, which causes wastage. Cutting the side plate also greatly reduces the structural integrity of the heat exchanger which can lead to damage during shipping, handling and installation.